AFFILIATES

Friday, August 31, 2012

Scientists at the Harvard School of Engineering and Applied Sciences have devised an ultra-thin, flat lens that focuses light without imparting the distortions of conventional lenses. Principal investigator Federico Capasso and his team have created the flat lens by plating a very thin wafer of silicon with a nanometre-thin layer of gold. Next, they striped away parts of the gold layer to leave behind an array of V-shaped structures, evenly spaced in rows across the surface. When Capasso’s group shines a laser onto the flat lens, these structures act as nano-antennas that capture the incoming light and hold onto it briefly before releasing it again. Those delays, which are precisely tuned across the surface of the lens, change the direction of the light in the same way that a thick glass lens would, with an important distinction. The flat lens eliminates geometric distortions, astigmatism and coma, and is completely scalable, which is why the physicists working on the project believe that in future, all the bulk components in the majority of optical systems can potentially be replaced by flat surfaces.